Dry weather persists today. Another strong winter storm will bring multiple feet of snow with major impacts expected once again over the foothills and mountains Saturday into early next week.
Discussion
Clear to partly cloudy skies cover interior NorCal early this morning as the weak short-wave pushes east into the Great Basin. Current temperatures are considerably milder across most of the region compared to 24 hours ago, particularly in the mountains where cloud cover is more extensive, and range from the 20s to mid 30s in the mountains to the mid 30s to mid 40s across the Central Valley.
Flat short-wave ridging will result in another day of dry weather for the region with generally light northerly winds through the Central Valley. Highs today will be similar to Thursday’s, though not as warm at the north end of the Sacramento Valley and in the mountains.
Attention then turns to the next impactful system that will arrive to northern California on Saturday. This storm will feature yet another round of heavy mountain snow, some foothill snow, Valley rain, and breezy southerly winds.
Onset of the precipitation will initially arrive for Shasta County early Saturday morning, then spreads south/east through the morning hours and day on Saturday. The most concerning impacts will be realized in the mountains where the new snow will pile onto an already-deep snow pack.
Heaviest snow is forecast to occur during the day on Saturday with the arrival initial band with heavy snow continuing into Sunday, particularly in the Sierra.
Snow levels with this storm will generally range from roughly 1000 to 2000 ft around Shasta County and 1500 to 2500 ft for locations in the Sierra. There could be periods with briefly lower snow levels, mainly on Sunday morning and Monday mornings.
Cold airmass will promote inflated snow ratios along with heavy snow totals on the order of multiple feet in the Sierra. Some locations may conceivably approach 4 feet, possibly even 5 feet along the Interstate 80 corridor above 4500 or 5000 ft elevation by the time the snow winds down early Monday.
The very real potential exists for excessive and prolonged delays and road closures as result of the heavy snow, blowing snow, and white-out conditions.
Breezy south/southwest winds accompanying this system may also cause fallen limbs/trees. Snow removal has become increasingly more challenging because of the deep snow pack, and this will only continue with more heavy snow accumulations.
Motorists should always check with CalTrans for the latest road conditions, restrictions, and closure information. Additionally, always listen to law enforcement and never drive beyond any road closure barriers.
Extended Discussion (Tuesday through Friday)
Ensembles and clusters keep a large scale upper level trough over the West Coast States through the end of the week. This will maintain cool and unsettled weather conditions over NorCal through the week.
Weak disturbances rotating through the trough will provide periods of light snow through Friday. Relatively low snow levels will bring snow down into the upper foothills at times. Current forecast snow amounts would suggest 2 to 3 inch per day rates, which could bring 4 day totals to near a foot in some areas.
Temperatures will be about 10 degrees below normal with highs in the 50’s and lows in the 30’s at Valley locations.